Marine Slow-Speed Engines' Cylinder Oil Lubrication Feed Rate Optimization in Real Operational Conditions

The paper presents results of research performed to find the most suitable cylinder-liner-lubricating-oil feed rates for lubrication of long-stroke, slow-speed marine engines to reduce cylinder oil consumption and reduce engines' maintenance costs. Obtained research data can be used to increase engines' reliability, reduce operational costs of the vessels, and improve energy efficiency on board ships. Using analysis of under-piston scavenge drain oil, research has been performed to find the relationship between various engines' operational factors and the wear intensity of cylinder liners and piston rings. Prediction models of the most suitable cylinder oil feed rates depend on the brand of cylinder oil and fuel actually in use, and the sulfur content in the fuel oil Verified in operation, the presented practical model can be used by engines' operators to set up cylinder oil feed rates with satisfactory cylinder liner and piston ring wear rates and cylinder oil consumption. It is underlined that analysis of scavenge drain oil properties gives an answer whether reduction of the cylinder oil lubricating feed rate is possible, information about the quality of lubrication of cylinder liners and piston rings, and can be used as a maintenance tool to maintain the serviceability and reliability of marine slow-speed engines.